"Mercy-hentai" is a combination of two words in the context of adult content, specifically hentai. Hentai refers to Japanese animated pornography or adult anime, and "mercy" is an English word that can be interpreted as showing kindness, compassion, or relief.
In this case, the tag "mercy-hentai" likely describes a hentai video where one or more characters show kindness, compassion, or mercy towards another character. This could involve acts of tenderness or emotional support within the context of the story. However, it can also be interpreted as a scene involving a dominant character showing "mercy" to a submissive character by engaging in less intense or painful sexual activities.
Remember that this tag is related to hentai, which may not appeal to everyone due to its nature and content. Hentai covers a wide range of themes, genres, and styles, so the specific meaning of "mercy-hentai" can vary depending on the video itself. As with all adult content, viewer discretion is advised.